Global energy consumption steadily outpaces the growth of economically viable renewable energy, and the amount of available fossil fuel resources continues to dwindle. Consequently, energy efficiency remains an important initiative. By improving efficiency, the global community can reduce energy consumption, and thereby conserve resources for the future without decreasing quality of life in the present.
One movement toward improving energy efficiency is to use electronic devices, such as sensors and microcontrollers in order to create intelligent, computerized networks to control and to monitor certain energy consuming features of buildings. Over the past decade, such systems, called building automation systems (BAS), have significantly improved the efficiency of certain energy end-use categories such as heating, ventilation and air conditioning (HVAC) and lighting, especially in commercial buildings. In fact, as the U.S. Energy Information Administration (EIA) has noted, the electricity consumption by HVAC and lighting per square foot of commercial floor space has been decreasing. Unfortunately, the category of plug loads (which refers to devices that plug into wall sockets and demand electricity) has proven more difficult to control and to manage, and thus it remains largely unaddressed.
Demonstrative of the challenges of improving the efficiency of plug loads is the trend that they, plug loads, outpace growth in commercial floor space to such a degree that the overall energy consumption of commercial buildings is still climbing. Currently, plug loads account for more than 20% of electricity usage in commercial buildings and are the fastest growing end-use category of electricity in the commercial sector. (U.S. Department of Energy, “Annual Energy Outlook 2012 Early Release,” 2012.) Similarly, in the residential setting, energy usage from HVAC and lighting is decreasing while energy usage from plug loads such as televisions, set top boxes, computers and other plugged in devices is growing. Experts project that this usage will continue to grow.
Recently, outlet control and monitoring devices have been developed to begin to address plug load energy inefficiency by monitoring power consumption and using computer technology to turn off power supplies to plugged in devices remotely, when not in use. Examples of this technology are disclosed in U.S. Patent Publication No. 2010-0070217, which published on Mar. 18, 2010, and U.S. Patent Publication No. 2010-0280978, which published on Nov. 4, 2010. While these technologies extend certain types of control ability to the previously unaddressed category of plug loads, there remain barriers to the practical implementation of a plug load energy efficiency system that have largely prevented integration of plug load control into BAS.